1. Field of the Invention
The present invention relates to a contention access method for wireless communication networks and, more particularly, to a hexanary-feedback contention access (HFCA) method for wireless communication networks, which estimates the quantity of mobile stations (MSs) by using probability density function (pdf).
2. Description of Related Art
In recent years, wireless communication networks have been widely developed to satisfy the various wireless communication requirements, so that people have expected Quality of Service (QoS) to be provided variously and rapid. When multiple MSs are connected to the wireless communication network for services, the MSs have to register first at a corresponding base station (BS) in the wireless communication network. However, a slot of the BS only allows only one MS to register. Therefore, when multiple MSs are registering at the same slot, these MSs respectively send registration data to a BS with the slot by an uplink, so that the BS receives a number of undistinguishable signals because signals sent by the MSs are interfered in and imposed on each other. As such, the BS sends a collision signal to the MSs by a downlink and accordingly the MSs need to further perform a random procedure such as Controlled slotted-Aloha (CS-Saloha) to determine whether or not to register at a subsequent slot. If the quantity of MSs trying to register in the next slot exceeds one, the aforementioned random procedure for collision has to be repeated. This results in a poor performance because the quantity of MSs to be registered cannot be estimated accurately.
Therefore, it is desirable to provide an improved contention access method to mitigate and/or obviate the aforementioned problems.